The invention relates to a closing arrangement for a vent line of a fuel tank that comprises a housing with an inlet and an outlet as well as a closing device and is actuated as a function of the Position of the vehicle, the closing device consisting of a mass part and a closing part interacting with the mass part, and the closing part closing off an outlet opening in the case of an inclined position of the vehicle.
In a known closing arrangement of the initially mentioned type described in German patent (DE-PS) No. 25 03 731, a conical chamber is provided inside the housing that expands in upward direction and in which a mass part is arranged and a closing part that is located on the upper surface of the mass part. In the case of an inclined or inverted position of the vehicle, the mass part slides along a guiding wall of the housing and presses the closing part into the outlet opening, whereby no more fuel can flow out through the outlet opening.
In practice, it was found that under extreme conditions, for example, (high outside temperatures and/or high altitudes), in the driving operation, an increased gasification of the fuel occurs, resulting in an increased flow of gas from the fuel tank into the vent line and the closing arrangement. As a result of this flow of gas and possibly as a result of shocks during the driving operation, the closing part may be pressed upward against the outlet opening and closes this outlet opening, which results in a pressure increase within the closing arrangement and in the fuel tank system. The pressure increase has the effect that the closing part, even in the normal position of the vehicle, is caught in the outlet opening, so that a perfect venting of the fuel tank will no longer exist.
It is an object of the invention to provide a closing arrangement that functions well even in the case of an increased gasification of the fuel.
According to the invention, this objective is achieved by providing a two chamber housing in the vent line with a mass part in one chamber and a closing element in the other chamber connected to one another by a connecting rod such that the mass part maintains the closing element in an open position unless the vehicle is tilted.
The main advantages achieved by means of the invention are that, as a result of the development of the housing and of the closing device, a closing arrangement is provided that functions perfectly in the case of high outside temperatures as well as at high altitudes and in all positions of the vehicle. By arranging the mass part, that interacts with the closing part via a connecting element, on top, it is achieved that the closing element, even in the case of a high gasification of the fuel, is not pressed upward against the connecting outlet opening between the two chambers.
In its preferred embodiments the guiding ribs that are arranged at the upper chamber receive the mass part that, to a certain extent, is freely movable, in which case flow-through ducts extend between the guiding ribs through which the fuel vapors can pass when the outlet opening is open. The star-shaped ribs that are provided at the lower chamber provide that the sealing surface disposed in front of the outlet opening is not damaged by the connecting element between the closing part and the mass part. When the vehicle is in an inclined or inverted position, the mass part slides along the guiding ribs and pulls the closing part against the outlet opening.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.